The present invention relates to the field of cotton processing and more particularly to the process of restoring moisture to cotton fibers.
During the processing of cotton at a gin, controlling cotton moisture is very important. High moisture in the seed cotton prior to separating the fibers from the seed makes the cotton very difficult to clean. Seed cotton driers are used to lower the fiber moisture often below 6% for optimum cleaning. While this very significantly aids the cleaning processes, the fibers are weakened at these low moisture levels. Although, moisture restoration systems operating just prior to ginning are sometimes used to reduce the fiber breakage during the aggressive saw ginning process, moisture addition systems are primarily used to restore moisture to the ginned lint at, or just following, the battery condenser and just prior to the baling press. The added moisture in the lint batt fed to the press reduces the forces of compression required to make the highly compacted fibers in the bale produced at the press. Also, the added moisture reduces the bulk of the cotton batt flowing into the press, increasing processing rates. Further, lint moisture content of 7½% is the industry approved top limit for moisture content in the bale. With the lint often approaching the battery condenser at less than 5%, the addition of 2% moisture (approximately 10 pounds per bale) becomes a significant monetary incentive.
For many years, there have been two methods for adding moisture to cotton fibers at the gin. One method is to spray atomized water on the cotton batt as it leaves the battery condenser. This method results in uneven application of the moisture that can result in areas of excessive moisture in the bale with resultant fiber quality deterioration. This method is under strong criticism. The current dominant method employs an air humidification device involving water spray nozzles discharged into a stream of heated air to increase the air moisture content. This moisturized air then is blown through the cotton fibers moving through the ginning process. The cotton fibers must be cooler than the humidified air to cause the air temperature to drop below the dew point thereby depositing moisture on the surfaces of the cotton fibers. This process is generally effective, but is subject to the variations in the ambient air. Both the ambient air temperature and relative humidity variations, from day to night and from hour to hour throughout the day, coupled with the changes in the temperature of the cotton batt make this process very difficult to control. Additionally, the cooling effect of the evaporation of the water spray into the heated air lowers the air temperature such that the temperature of the moisturized air is sometimes not sufficiently higher than the cotton fiber temperature to cause the air to give up the needed amount of moisture to the cotton. Therefore, the average moisture addition with this method is limited and results in bale moisture averages well under the 7½% moisture level authorized by the industry leaders. Additionally, the water spray nozzles used to add moisture to the heated air require considerable effort to maintain their atomizing efficiency.